1. Field of the Invention
The present invention relates to a die set for welding fins and a base plate of a heat sink, it is used to complete fixing of the U shaped fins and the base plate of the heat sink by welding. It has the object to increase heat-sinking efficiency and to render the welding process to finish quickly.
2. Description of the Prior Art
Conventional heat sinks are all made of aluminum by virtue that aluminum has high heat conduction efficiency and low cost of material. The structure of such a conventional heat sink is shown in FIG. 1, and is comprised of a base plate 1 and a plurality of heat sinking fins 2 provided on the top of the base plate 1. Wherein, the bottom of the base plate 1 is mounted on the top surface of an appliance 3 to be processed for heat sinking. While the heat sinking fins 2 are mounted above the base plate 1 in order to fast transmit the heat with high temperature absorbed by the base plate 1 to each heat sinking fin 2. Then by convection of the heat sinking fins 2 with cool air, the high temperature on the appliance 3 can be reduced.
When in manufacturing of a conventional heat sink, extrusion process is always used to integrally make it by virtue that aluminum has high ductility and low melting point. However, the conventional heat sink made by extrusion process has the defect that the heat sinking fins in the extrusion process are supposed not to be too thin, and the distance between every two fins shall not be too short. Otherwise, material supply for the fins in the extrusion process will be sometimes smooth and sometimes intermittent. Therefore, amount of the heat sinking fins is limited, and heat sinking area will be reduced. On the contrary, thicker fins cost higher, and are heavier; they are not good for computers which develop very fast nowadays.
In view of the above mentioned defects of the extrusion process for heat sinks, one kind of heat sink as shown in FIG. 2 and 3 has been developed in the art. Construction of the heat sink includes serially bending a plurality of heat sinking fins 20 to form a plurality of U shaped bends; the bottom surfaces of the bends are plain. A base plate 10 provided for the heat sinking fins 20 is in the form of a plain plate. The plain bottom surfaces of the bends are placed on and stuck to the top surface of the base plate 10; and assembling of the heat sink is completed.
Such a heat sink which is combined from the base plate 10 and the heat sinking fins 20 manufactured separately forms a structure having serial U shaped bends, thereby the thickness of the heat sinking fins 20 can be reduced. And the effects of heat conducting and heat sinking can thus be better; this can exactly overcome the defects of the first mentioned conventional heat sinks made integrally. However, there is no appropriate equipment or tool for constructing such a combined heat sink from the base plate 10 and the heat sinking fins 20. Only glue is applied in advance at the areas where the base plate 10 and the heat sinking fins 20 are to be combined mutually. This is inconvenient for automatic production. Evidently, glue especially adversely influences the heat conducting effect between these two parts.